Vibration-damping rotor assembly

ABSTRACT

A rotor assembly comprising: an inner rotor and an outer rotor for rotating in a magnetic field of a motor, the inner rotor comprising a main inner rotor cavity, and a plurality of first holes being formed between the inner rotor and the outer rotor; two side boards, each side board having a main side board cavity, and being perforated by a plurality of second holes; two damping elements each damping element comprising a main damping element cavity; a plurality of rubber sleeves, each rubber sleeve having a rubber sleeve lip; and a plurality of third holes; an axle; and a plurality of positioning pins.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 11/343,633 filed Jan. 31, 2006, now pending, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a rotor assembly, and more particularly to a rotor assembly of a motor which reduces vibrations of the rotor resulting from high frequency resonance of the electric current.

2. Description of the Related Art

A rotor assembly and an axle of a motor are two isolated parts; conventionally, there is no connector sandwiched therebetween. Therefore, when the rotor assembly is rotated, its movement is not smooth due to high frequency resonance of the induced current. As such, the rotation of the axle generates noises and may even cause destructive resonance. Adding damping elements between the rotor and the axle reduces noise. However, the damping elements are complicated and expensive.

To overcome these shortcomings, this invention provides an improved vibration-damping rotor assembly.

SUMMARY OF THE INVENTION

One objective of this invention is to provide a vibration-damping rotor assembly to damp out vibration caused by the high frequency resonance of current.

In one embodiment of the invention provided is a rotor assembly comprising an inner rotor and an outer rotor for rotating in a magnetic field of a motor, the inner rotor comprising a main inner rotor cavity, and a plurality of first holes being formed between the inner rotor and the outer rotor; two side boards, each side board having a main side board cavity, and being perforated by a plurality of second holes; two damping elements each damping element comprising a main damping element cavity; a plurality of rubber sleeves, each rubber sleeve having a rubber sleeve lip; and a plurality of third holes; an axle; and a plurality of positioning pins.

In a class of this embodiment, the axle extends through the main inner rotor cavity, two the main side board cavities, and two the main damping element cavities; the main side board body extends through the main damping element cavity and into the main rotor cavity; the plurality of the rubber sleeves is disposed respectively in the plurality of the first holes; the rubber sleeve lip forms a buffer between the inner rotor/outer rotor and the side board; and the plurality of the positioning pins traverses the first holes, the second holes, and the third holes, respectively

In a class of this embodiment, the inner rotor and the outer rotor are firmly sandwiched between two the side boards and two the damping elements.

In a class of this embodiment, the rotor assembly is layered from top to bottom as follows: side board, damping element, inner rotor/outer rotor, damping element, side board.

In a class of this embodiment, the number of the first holes is equal to the number of the second holes and is equal to the number of the third holes, and is equal to the number of the positioning pins.

In a class of this embodiment, the number of the first holes, the number of the second holes, the number of the third holes, and the number of the positioning pins is each between 2 and 60, and particularly, is each 6.

In a class of this embodiment, the damping element, the side boards, and the positioning pins are made, at least in part, of vibration-damping material, such as rubber.

In a class of this embodiment, the rubber sleeve lip is washer-shaped, i.e., is in the shape of a circle having a centrally disposed circular cavity.

In a class of this embodiment, the positioning pins comprise pin main body and pin head, the pin head abutting the side board and securing the pin body within the first holes, the second holes, and the third holes, respectively.

In another embodiment of the invention provided is a rotor assembly comprising: an outer rotor and an inner rotor each having a top side and a bottom side, a plurality of first through holes being formed between the outer rotor and the inner rotor; a first side board and a second side board; a first damping element and a second damping element, each having a plurality of hollow cylindrical protrusions; and a plurality of positioning pins.

In a class of this embodiment, the first damping element is disposed against the top sides of the outer rotor and the inner rotor so that the hollow cylindrical protrusions protrude into the first through holes from the top side; and the first damping element is sandwiched between the first side board and the inner rotor and the outer rotor by means of the positioning pins.

In a class of this embodiment, the second damping element is disposed against the bottom sides of the outer rotor and the inner rotor so that the hollow cylindrical protrusions protrude into the first through holes from the bottom side; and the second damping element is sandwiched between the second side board and the inner rotor and the outer rotor by means of the positioning pins.

In a class of this embodiment, the positioning pins are greater in length than the cross-sectional width of the rotor, the first side board, the second side board, the first damping element, and the second damping element combined.

In a class of this embodiment, the number of the first through holes is equal to the number of the hollow cylindrical protrusions, and is equal to the number of the positioning pins.

In a class of this embodiment, the number of the first holes, the number of the hollow cylindrical protrusions, and the number of the positioning pins is each between 2 and 60, and particularly, 6.

In a class of this embodiment, the damping elements, the side boards, and the positioning pins are made, at least in part, of vibration-damping material, such as, e.g., rubber.

In a class of this embodiment, the positioning pins comprise pin main body and pin head, the pin head abutting the first side board or the second side board.

In another embodiment of the invention provided is a rotor assembly comprising: a permanent magnet rotor for an electric motor, comprising an inner rotor and an outer rotor and a plurality of through holes formed between the inner rotor and the outer rotor; a plurality of positioning pins and means for reducing vibrations of the rotor assembly.

In a class of this embodiment, the means for reducing vibrations partially fills the through holes from both sides of the permanent magnet rotor and the means is securely attached to the permanent magnet rotor with the positioning pins.

In a class of this embodiment, the positioning pins protrude out of the inner and outer rotors and the means for reducing vibration.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinbelow with reference to accompanying drawings, in which:

FIGS. 1 and 2 are cross-sectional exploded views of the rotor assembly according to one embodiment of the invention;

FIG. 3 is a cross-sectional view of the rotor assembly;

FIG. 4 is a cross-sectional view taken from line A-A of FIG. 3; and

FIG. 5 is a cross-sectional view of the rotor assembly according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1-3, the rotor assembly comprises an inner rotor (2) and an outer rotor (3) for rotating in a magnetic field of a motor, two side boards (9), two damping elements (10), an axle (1), and a plurality of positioning pins (8). The inner rotor (2) comprises a main inner rotor cavity (20). The outer rotor (3) comprises a main outer rotor cavity (30). A plurality of first holes (4) is respectively defined between the outer periphery of the inner rotor (2) and the inner periphery of the outer rotor (3) so as to receive therein a damping element, as shown in FIG. 3.

The damping element may be a rubber block (5), as shown in FIG. 5. In a different embodiment of the present invention, the damping element may be a rubber ring (10) having apertures (7) which are defined in the rubber ring (10) to receive therein a damping pin (8) and to correspond to the first holes (4) of the inner rotor (2) and the outer rotor (3), respectively.

The quantity of the first holes (4) of the inner rotor (2) and the outer rotor (3) is between 2 and 60. The shape of the first hole (4) may be circular or rectangular such that the shape of the damping element may also be circular or rectangular to match the shape of the first holes (4). Also, the first holes (4) of the inner rotor (2) may or may not communicate with the holes (4) of the outer rotor (3) so that different embodiments of the present invention are applied to adapt to the variation of the communication status of the holes (4) of the inner rotor (2) and the outer rotor (3).

Each side board (9) is flat and disc-shaped. Each side board (9) has a main side board cavity (90) and is perforated by a plurality of second holes (91). The side boards (9) are provided to secure the positions of the inner rotor (2) and the outer rotor (3).

Each damping element comprises a main damping element cavity (60); a plurality of rubber sleeves (62), each rubber sleeve having a rubber sleeve lip (63); and a plurality of third holes (7). Because the side boards (9) are flat, they do not extend into the main damping cavity (60).

The axle (1) extends through the main inner rotor cavity (20), the main outer rotor cavity (30), two the main side board cavities (90), and two the main damping element cavities (60). A plurality of the rubber sleeves (62) is disposed respectively in the plurality of the first holes (4). The rubber sleeve lip (63) forms a buffer between the inner rotor (2)/outer rotor (3) and the side board (9). A plurality of positioning pins (8) traverses the first holes (4), the second holes (91), and the third holes (7), respectively; that is one positioning pin (8) traverses one first hole (4), one second hole (91), and one third hole (7).

Preferably, the diameter of the damping pin (8) is larger than that of the apertures (7) such that after the damping pin (8) is inserted into a corresponding one of the apertures (7), the aperture (7) is expanded in dimension and the rubber ring (10) is deformed so that a damping effect is provided between the inner rotor (2) and the outer rotor (3). Preferably, the positioning pins (8) comprise pin main body (81) and pin head (82).

With reference to FIG. 3, the inner rotor (2) and the outer rotor (3) are firmly sandwiched between two the side boards (9) and two the damping elements (7, 10). The rotor assembly is layered from top to bottom as follows: side board (9), damping element (7, 10), inner rotor (2) and outer rotor (3), damping element (7, 10), and side board (9). Positioning pins (8) are mounted through the side boards (9), the damping element (7, 10) and the inner/outer rotor (2, 3) to stably hold the damping elements (7, 10) between the side boards (9) and the rotor (2, 3). The second holes (91) are aligned with the third holes (7) that, in turn, align with the first holes (4) such that the positioning pins (8) protrude into the aligned first holes (4), the second holes (91) and the third holes (7) to assemble the rotor assembly after the axle (1) is first mounted through the side boards (9), the damping element (7, 10) and the rotor (2, 3). Preferably, the damping element (7, 10) in this embodiment comprises a rubber sleeve (62) mounted in a corresponding first hole (4) of the rotor (2, 3) around a corresponding positioning pin (8). Preferably, a quantity of the first holes is between 2 and 60. Furthermore, the positioning pins (8) are made of metal or rubber or combination thereof.

With reference to FIG. 5, the rubber sleeves are interconnected via a rubber ring and the third holes (7) are still defined in the rubber sleeves to allow the extension of the positioning pins (8) into the rotor (2, 3).

As a consequence of the provision of the rotor assembly, when the outer rotor (3) is rotated and vibrated due to the high frequency resonance of the current, because the damping structure, i.e., the rubber sleeves (62) in the first holes (4) of the rotor (2, 3), exists between the rotor (2, 3) and the side boards (9), the vibration from the rotor (2, 3) is effectively damped so that the force transmitted to the axle (1) is smooth and thus noise and vibration generated by the axle (1) is effectively reduced.

This invention is not to be limited to the specific embodiments disclosed herein and modifications for various applications and other embodiments are intended to be included within the scope of the appended claims. While this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.

All publications and patent applications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains. All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application mentioned in this specification was specifically and individually indicated to be incorporated by reference. 

1. A rotor assembly comprising: an inner rotor and an outer rotor for rotating in a magnetic field of a motor, said inner rotor comprising a main inner rotor cavity, and a plurality of first holes being formed between said inner rotor and said outer rotor; two side boards, each side board having a main side board body; a main side board cavity, and being perforated by a plurality of second holes; two damping elements, each damping element comprising a main damping element cavity; a plurality of rubber sleeves, each rubber sleeve having a rubber sleeve lip; and a plurality of third holes; an axle; and a plurality of positioning pins; wherein said axle extends through said main inner rotor cavity, two said main side board cavities, and two said main damping element cavities; said main side board body extends over said main damping element cavity and partially over said main rotor cavity; said plurality of said rubber sleeves is disposed respectively in said plurality of said first holes; said rubber sleeve lip forms a buffer between said inner rotor/outer rotor and said side board; said plurality of said positioning pins traverses said first holes, said second holes, and said third holes, respectively; said damping element, said side boards, and said positioning pins are made of vibration-damping material, said inner rotor and said outer rotor are firmly sandwiched between two said side boards and two said damping elements, and the rotor assembly is layered from one end to another as follows: side board, damping element, inner rotor/outer rotor, damping element, side board.
 2. The rotor assembly of claim 1, wherein the number of said first holes is equal to the number of said second holes and is equal to the number of said third holes, and is equal to the number of said positioning pins.
 3. The rotor of claim 1, wherein the number of said first holes, the number of said second holes, the number of said third holes, and the number of said positioning pins is each between 2 and
 60. 4. The rotor assembly of claim 1, wherein the number of said first holes, the number of said second holes, the number of said third holes, and the number of said positioning pins is each
 6. 5. The rotor assembly of claim 1, wherein said damping elements, said side boards, and said positioning pins comprise rubber.
 6. The rotor assembly of claim 1, wherein said rubber sleeve lip is washer-shaped.
 7. The rotor assembly of claim 1, wherein said positioning pins comprise pin main body and pin head, said pin head abutting said side board and securing said pin body within said first holes, said second holes, and said third holes, respectively. 